Concepts and Principles Flashcards
7 cards from real CEM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Concepts and Principles flashcards as text
What distinguishes a 'Type II' energy audit from a 'Type I' energy audit per ASHRAE guidelines?
Answer: Type II includes detailed analysis and savings potential for capital-intensive ECMs
A Type II audit (Energy Survey and Engineering Analysis) provides detailed engineering analysis and cost-benefit calculations for capital-intensive energy conservation measures.
Which principle underlies the concept of 'combined heat and power' (CHP) systems?
Answer: Simultaneously generating electricity and capturing waste heat for useful thermal applications
CHP (cogeneration) captures heat that would otherwise be wasted from electricity generation and uses it for space heating, process heat, or cooling, improving overall fuel efficiency.
What is the 'Rankine cycle' most commonly associated with in energy systems?
Answer: Steam-based power generation in thermal power plants
The Rankine cycle describes the thermodynamic process used in steam power plants, where water is heated to steam, expanded through a turbine to generate work, then condensed and recycled.
In energy management, what does 'retro-commissioning' involve?
Answer: Systematic investigation and optimization of existing building systems to restore peak performance
Retro-commissioning optimizes existing building systems that were never properly commissioned or have drifted from optimal performance, typically without capital investment in new equipment.
The 'payback period' method of evaluating energy projects has which significant limitation?
Answer: It ignores the time value of money and cash flows beyond the payback point
Simple payback does not discount future savings and ignores all benefits occurring after the payback period, potentially misranking long-lived, high-return projects.
What is 'peak shaving' in the context of electrical demand management?
Answer: Reducing demand during high-demand periods to lower peak demand charges
Peak shaving reduces electricity demand during the utility's peak periods—through load curtailment, battery storage, or on-site generation—to minimize demand charges.
What energy content (approximate) is equivalent to one kilowatt-hour (kWh) of electricity?
Answer: 3,412 BTU
One kWh equals approximately 3,412 BTU, a fundamental conversion factor used throughout energy management calculations.